João Paulo Bender

Optimization of Enzymatic Production of Biodiesel from Castor Oil in Organic Solvent Medium

We studied the production of fatty acid ethyl esters from castor oil using n-hexane as solvent and two commercial lipases, Novozym 435 and Lipozyme IM, as catalysts. For this purpose, a Taguchi experimental design was adopted considering the following variables: temperature (35–65°C), water (0–10 wt/wt%), and enzyme (5–20 wt/wt%) concentrations and oil-to-ethanol molar ratio (1∶3 to 1∶10). An empirical model was then built so as to assess the main and cross-variable effects on the reaction conversion and also to maximize biodiesel production for each enzyme. For the system containing Novozym 435 as tatalyst the maximum conversion obtained was 81.4% at 65°C, enzyme concentration of 20 wt/wt%, water concentration of 0 wt/wt%, and oil-to-ethanol molar ratio of 1∶10. When the catalyst was Lipozyme IM, a conversion as high as 98% was obtained at 65°C, enzyme concentration of 20 wt/wt%, water concentration of 0 wt/wt%, and oil-to-ethanol molar ratio of 1∶3.

Optimization of alkaline transesterification of soybean oil and castor oil for biodiesel production

This article reports experimental data on the production of fatty acid ethyl esters from refined and degummed soybean oil and castor oil using NaOH as catalyst. The variables investigated were temperature (30–70°C), reaction time (1–3 h), catalyst concentration (0.5–1.5 w/wt%), and oil-to-ethanol molar ratio (1:3–1:9). The effects of process variables on the reaction conversion as well as the optimum experimental conditions are presented. The results show that conversions >95% were achieved for all systems investigated. In general, an increase in reaction temperature, reaction time, and in oil-to-ethanol molar ratio led to an enhancement in reaction conversion, whereas an opposite trend was verified with respect to catalyst concentration.

Kinetics of Enzyme-Catalyzed Alcoholysis of Soybean Oil in n-Hexane

This work investigated the production of fatty acid ethyl esters (FAEEs) from soybean oil using n-hexane as solvent and two commercial lipases as catalysts, Novozym 435 and Lipozyme IM. A Taguchi experimental design was adopted considering the variables temperature (35-65 degrees C), addition of water (0-10 wt/wt%), enzyme (5-20 wt/wt%) concentration, and oil-to-ethanol molar ratio (1:3-1:10). It is shown that complete conversion in FAEE is achieved for some experimental conditions. The effects of process variables on reaction conversion and kinetics of the enzymatic reactions are presented for all experimental conditions investigated in the factorial design.

Addendum to issue 1 - ENZITEC 2012Influence of ultrasound and compressed liquefied petroleum gas on xylanase activity

Abstract Xylanase treated with ultrasound showed activities about two times higher than those obtained in its absence for temperatures ranging from 39 to 47°C. In the absence of ultrasound the enzyme activity was about 4–10 times higher compared with the activities determined in the presence of ultrasound for temperatures higher than 56°C. Treatment with compressed LPG led to an increase of about 250% in the enzyme activity for a system pressure of 30 bar, 50°C and 1 h of exposure. On the other hand, it was shown that enzyme treatment combining compressed LPG and ultrasound did not improve xylanase activity under any experimental conditions tested. These results obtained here are promising for industrial application in the enzymatic hydrolysis of lignocellulose for the production of fuels and chemicals, since rapid treatment of xylanase with compressed LPG or ultrasound is a novel procedure which provided a significant increase in activity.

High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE), liquid-liquid (LLE) and vapor-liquid-liquid (VLLE) equilibrium were recorded. It was experimentally observed that, at a given temperature and surfactant content, an increase in the concentration of glycerol/oil ratio led to a pronounced increase in the slope of the liquid-liquid coexistence curve. A comparison with results reported for the same system but using propane as solvent showed that much lower pressure transition values are obtained when using n-butane.

Effect of pretreatments on corn stalk chemical properties for biogas production purposes

Different pretreatments were evaluated on corn stalk (Zea mays) applied as a lignocellulosic source in anaerobic co-digestion with swine manure, using sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) for biogas production purposes. Using H2SO4 we achieved a 75.1% removal of the hemicellulose fraction, in low acid concentrations (0.75% v.v-1). However, this technique inhibited the co-digestion process. Pretreatment with 12% of H2O2 (pH 11.5) increased the cellulose fraction by 73.4% and reduced the lignin content by 71.6%. This pretreatment is recommended for biogas production, as it increased the final volume of biogas by 22% and reduced the digestion time by one third. So, a promising alternative was obtained in order to facilitate the anaerobic digestion of the carbohydrates present in this biomass.

The effects of ultrasound-assisted extraction on polyphenolics compounds obtained from Physalis angulata using response surface approach

Total polyphenols content (TPC), including flavonoids (rutin, mangiferin and kaempferol) and phenolic acids (gallic, caffeic and ellagic acid) from Physalis angulata were recovered by Ultrasound-Assisted Extraction and quantified by UV–vis and HPLC analysis. Process parameters were assessed through a Central Composite Rotatable Design (CCRD) and a model with regression coefficient equal to 0.9640, was used to establish the optimum conditions together with its respective response surfaces. The increase of ethanol percentage and solid-liquid ratio promoted a decrease on TPC but, on the other hand, the increase in the temperature led to an increase in the extraction of these compounds. Experimental results indicated a maximum amount of total polyphenols of 1.039 mg Gallic Acid Eqivalent (GAE) g -1 of extract, 104.88, 4.04, 8.37, 58.28, 13.26 and 1.87mg.L -1 for gallic acid, caffeic acid, ellagic acid, rutin, mangiferin and kaempferol, respectively.

Pretreatment of lignocellulosic biomass using ultrasound aiming at obtaining fermentable sugar

Abstract This study aims to evaluate the activity of the cellulase enzyme forward the use of ultrasound technology in different conditions of temperature, pH and exposure time, as well, to match the steps of pretreatment and enzymatic hydrolysis in one step. A central composite design (CCRD) and response surface analysis were used to evaluate the effect of ultrasound power, temperature and pH on enzyme activity. Optimum condition in the studied range was 30% for ultrasound power, pH 4.6 and 50 °C, yielding an enzyme activity of 15.5 UPF/mL. From this, we carried out kinetics of enzymatic hydrolysis on filter paper and bagasse malt, in optimized conditions. Total reducing sugars (TRS) were 3.85 and 0.46 mg/mL when the filter paper and bagasse malt were used as substrate, respectively. Ultrasound showed to be a good technology to increase the enzyme activity aiming to intensify enzymatic processes.